1 /* 2 * Squashfs - a compressed read only filesystem for Linux 3 * 4 * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008 5 * Phillip Lougher <phillip (at) lougher.demon.co.uk> 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License 9 * as published by the Free Software Foundation; either version 2, 10 * or (at your option) any later version. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program; if not, write to the Free Software 19 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. 20 * 21 * inode.c 22 */ 23 24 /* 25 * This file implements code to create and read inodes from disk. 26 * 27 * Inodes in Squashfs are identified by a 48-bit inode which encodes the 28 * location of the compressed metadata block containing the inode, and the byte 29 * offset into that block where the inode is placed (<block, offset>). 30 * 31 * To maximise compression there are different inodes for each file type 32 * (regular file, directory, device, etc.), the inode contents and length 33 * varying with the type. 34 * 35 * To further maximise compression, two types of regular file inode and 36 * directory inode are defined: inodes optimised for frequently occurring 37 * regular files and directories, and extended types where extra 38 * information has to be stored. 39 */ 40 41 #include <linux/fs.h> 42 #include <linux/vfs.h> 43 #include <linux/zlib.h> 44 45 #include "squashfs_fs.h" 46 #include "squashfs_fs_sb.h" 47 #include "squashfs_fs_i.h" 48 #include "squashfs.h" 49 50 /* 51 * Initialise VFS inode with the base inode information common to all 52 * Squashfs inode types. Sqsh_ino contains the unswapped base inode 53 * off disk. 54 */ 55 static int squashfs_new_inode(struct super_block *sb, struct inode *inode, 56 struct squashfs_base_inode *sqsh_ino) 57 { 58 int err; 59 60 err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->uid), &inode->i_uid); 61 if (err) 62 return err; 63 64 err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->guid), &inode->i_gid); 65 if (err) 66 return err; 67 68 inode->i_ino = le32_to_cpu(sqsh_ino->inode_number); 69 inode->i_mtime.tv_sec = le32_to_cpu(sqsh_ino->mtime); 70 inode->i_atime.tv_sec = inode->i_mtime.tv_sec; 71 inode->i_ctime.tv_sec = inode->i_mtime.tv_sec; 72 inode->i_mode = le16_to_cpu(sqsh_ino->mode); 73 inode->i_size = 0; 74 75 return err; 76 } 77 78 79 struct inode *squashfs_iget(struct super_block *sb, long long ino, 80 unsigned int ino_number) 81 { 82 struct inode *inode = iget_locked(sb, ino_number); 83 int err; 84 85 TRACE("Entered squashfs_iget\n"); 86 87 if (!inode) 88 return ERR_PTR(-ENOMEM); 89 if (!(inode->i_state & I_NEW)) 90 return inode; 91 92 err = squashfs_read_inode(inode, ino); 93 if (err) { 94 iget_failed(inode); 95 return ERR_PTR(err); 96 } 97 98 unlock_new_inode(inode); 99 return inode; 100 } 101 102 103 /* 104 * Initialise VFS inode by reading inode from inode table (compressed 105 * metadata). The format and amount of data read depends on type. 106 */ 107 int squashfs_read_inode(struct inode *inode, long long ino) 108 { 109 struct super_block *sb = inode->i_sb; 110 struct squashfs_sb_info *msblk = sb->s_fs_info; 111 u64 block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table; 112 int err, type, offset = SQUASHFS_INODE_OFFSET(ino); 113 union squashfs_inode squashfs_ino; 114 struct squashfs_base_inode *sqshb_ino = &squashfs_ino.base; 115 116 TRACE("Entered squashfs_read_inode\n"); 117 118 /* 119 * Read inode base common to all inode types. 120 */ 121 err = squashfs_read_metadata(sb, sqshb_ino, &block, 122 &offset, sizeof(*sqshb_ino)); 123 if (err < 0) 124 goto failed_read; 125 126 err = squashfs_new_inode(sb, inode, sqshb_ino); 127 if (err) 128 goto failed_read; 129 130 block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table; 131 offset = SQUASHFS_INODE_OFFSET(ino); 132 133 type = le16_to_cpu(sqshb_ino->inode_type); 134 switch (type) { 135 case SQUASHFS_REG_TYPE: { 136 unsigned int frag_offset, frag_size, frag; 137 u64 frag_blk; 138 struct squashfs_reg_inode *sqsh_ino = &squashfs_ino.reg; 139 140 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, 141 sizeof(*sqsh_ino)); 142 if (err < 0) 143 goto failed_read; 144 145 frag = le32_to_cpu(sqsh_ino->fragment); 146 if (frag != SQUASHFS_INVALID_FRAG) { 147 frag_offset = le32_to_cpu(sqsh_ino->offset); 148 frag_size = squashfs_frag_lookup(sb, frag, &frag_blk); 149 if (frag_size < 0) { 150 err = frag_size; 151 goto failed_read; 152 } 153 } else { 154 frag_blk = SQUASHFS_INVALID_BLK; 155 frag_size = 0; 156 frag_offset = 0; 157 } 158 159 inode->i_nlink = 1; 160 inode->i_size = le32_to_cpu(sqsh_ino->file_size); 161 inode->i_fop = &generic_ro_fops; 162 inode->i_mode |= S_IFREG; 163 inode->i_blocks = ((inode->i_size - 1) >> 9) + 1; 164 squashfs_i(inode)->fragment_block = frag_blk; 165 squashfs_i(inode)->fragment_size = frag_size; 166 squashfs_i(inode)->fragment_offset = frag_offset; 167 squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block); 168 squashfs_i(inode)->block_list_start = block; 169 squashfs_i(inode)->offset = offset; 170 inode->i_data.a_ops = &squashfs_aops; 171 172 TRACE("File inode %x:%x, start_block %llx, block_list_start " 173 "%llx, offset %x\n", SQUASHFS_INODE_BLK(ino), 174 offset, squashfs_i(inode)->start, block, offset); 175 break; 176 } 177 case SQUASHFS_LREG_TYPE: { 178 unsigned int frag_offset, frag_size, frag; 179 u64 frag_blk; 180 struct squashfs_lreg_inode *sqsh_ino = &squashfs_ino.lreg; 181 182 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, 183 sizeof(*sqsh_ino)); 184 if (err < 0) 185 goto failed_read; 186 187 frag = le32_to_cpu(sqsh_ino->fragment); 188 if (frag != SQUASHFS_INVALID_FRAG) { 189 frag_offset = le32_to_cpu(sqsh_ino->offset); 190 frag_size = squashfs_frag_lookup(sb, frag, &frag_blk); 191 if (frag_size < 0) { 192 err = frag_size; 193 goto failed_read; 194 } 195 } else { 196 frag_blk = SQUASHFS_INVALID_BLK; 197 frag_size = 0; 198 frag_offset = 0; 199 } 200 201 inode->i_nlink = le32_to_cpu(sqsh_ino->nlink); 202 inode->i_size = le64_to_cpu(sqsh_ino->file_size); 203 inode->i_fop = &generic_ro_fops; 204 inode->i_mode |= S_IFREG; 205 inode->i_blocks = ((inode->i_size - 206 le64_to_cpu(sqsh_ino->sparse) - 1) >> 9) + 1; 207 208 squashfs_i(inode)->fragment_block = frag_blk; 209 squashfs_i(inode)->fragment_size = frag_size; 210 squashfs_i(inode)->fragment_offset = frag_offset; 211 squashfs_i(inode)->start = le64_to_cpu(sqsh_ino->start_block); 212 squashfs_i(inode)->block_list_start = block; 213 squashfs_i(inode)->offset = offset; 214 inode->i_data.a_ops = &squashfs_aops; 215 216 TRACE("File inode %x:%x, start_block %llx, block_list_start " 217 "%llx, offset %x\n", SQUASHFS_INODE_BLK(ino), 218 offset, squashfs_i(inode)->start, block, offset); 219 break; 220 } 221 case SQUASHFS_DIR_TYPE: { 222 struct squashfs_dir_inode *sqsh_ino = &squashfs_ino.dir; 223 224 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, 225 sizeof(*sqsh_ino)); 226 if (err < 0) 227 goto failed_read; 228 229 inode->i_nlink = le32_to_cpu(sqsh_ino->nlink); 230 inode->i_size = le16_to_cpu(sqsh_ino->file_size); 231 inode->i_op = &squashfs_dir_inode_ops; 232 inode->i_fop = &squashfs_dir_ops; 233 inode->i_mode |= S_IFDIR; 234 squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block); 235 squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset); 236 squashfs_i(inode)->dir_idx_cnt = 0; 237 squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode); 238 239 TRACE("Directory inode %x:%x, start_block %llx, offset %x\n", 240 SQUASHFS_INODE_BLK(ino), offset, 241 squashfs_i(inode)->start, 242 le16_to_cpu(sqsh_ino->offset)); 243 break; 244 } 245 case SQUASHFS_LDIR_TYPE: { 246 struct squashfs_ldir_inode *sqsh_ino = &squashfs_ino.ldir; 247 248 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, 249 sizeof(*sqsh_ino)); 250 if (err < 0) 251 goto failed_read; 252 253 inode->i_nlink = le32_to_cpu(sqsh_ino->nlink); 254 inode->i_size = le32_to_cpu(sqsh_ino->file_size); 255 inode->i_op = &squashfs_dir_inode_ops; 256 inode->i_fop = &squashfs_dir_ops; 257 inode->i_mode |= S_IFDIR; 258 squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block); 259 squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset); 260 squashfs_i(inode)->dir_idx_start = block; 261 squashfs_i(inode)->dir_idx_offset = offset; 262 squashfs_i(inode)->dir_idx_cnt = le16_to_cpu(sqsh_ino->i_count); 263 squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode); 264 265 TRACE("Long directory inode %x:%x, start_block %llx, offset " 266 "%x\n", SQUASHFS_INODE_BLK(ino), offset, 267 squashfs_i(inode)->start, 268 le16_to_cpu(sqsh_ino->offset)); 269 break; 270 } 271 case SQUASHFS_SYMLINK_TYPE: 272 case SQUASHFS_LSYMLINK_TYPE: { 273 struct squashfs_symlink_inode *sqsh_ino = &squashfs_ino.symlink; 274 275 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, 276 sizeof(*sqsh_ino)); 277 if (err < 0) 278 goto failed_read; 279 280 inode->i_nlink = le32_to_cpu(sqsh_ino->nlink); 281 inode->i_size = le32_to_cpu(sqsh_ino->symlink_size); 282 inode->i_op = &page_symlink_inode_operations; 283 inode->i_data.a_ops = &squashfs_symlink_aops; 284 inode->i_mode |= S_IFLNK; 285 squashfs_i(inode)->start = block; 286 squashfs_i(inode)->offset = offset; 287 288 TRACE("Symbolic link inode %x:%x, start_block %llx, offset " 289 "%x\n", SQUASHFS_INODE_BLK(ino), offset, 290 block, offset); 291 break; 292 } 293 case SQUASHFS_BLKDEV_TYPE: 294 case SQUASHFS_CHRDEV_TYPE: 295 case SQUASHFS_LBLKDEV_TYPE: 296 case SQUASHFS_LCHRDEV_TYPE: { 297 struct squashfs_dev_inode *sqsh_ino = &squashfs_ino.dev; 298 unsigned int rdev; 299 300 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, 301 sizeof(*sqsh_ino)); 302 if (err < 0) 303 goto failed_read; 304 305 if (type == SQUASHFS_CHRDEV_TYPE) 306 inode->i_mode |= S_IFCHR; 307 else 308 inode->i_mode |= S_IFBLK; 309 inode->i_nlink = le32_to_cpu(sqsh_ino->nlink); 310 rdev = le32_to_cpu(sqsh_ino->rdev); 311 init_special_inode(inode, inode->i_mode, new_decode_dev(rdev)); 312 313 TRACE("Device inode %x:%x, rdev %x\n", 314 SQUASHFS_INODE_BLK(ino), offset, rdev); 315 break; 316 } 317 case SQUASHFS_FIFO_TYPE: 318 case SQUASHFS_SOCKET_TYPE: 319 case SQUASHFS_LFIFO_TYPE: 320 case SQUASHFS_LSOCKET_TYPE: { 321 struct squashfs_ipc_inode *sqsh_ino = &squashfs_ino.ipc; 322 323 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, 324 sizeof(*sqsh_ino)); 325 if (err < 0) 326 goto failed_read; 327 328 if (type == SQUASHFS_FIFO_TYPE) 329 inode->i_mode |= S_IFIFO; 330 else 331 inode->i_mode |= S_IFSOCK; 332 inode->i_nlink = le32_to_cpu(sqsh_ino->nlink); 333 init_special_inode(inode, inode->i_mode, 0); 334 break; 335 } 336 default: 337 ERROR("Unknown inode type %d in squashfs_iget!\n", type); 338 return -EINVAL; 339 } 340 341 return 0; 342 343 failed_read: 344 ERROR("Unable to read inode 0x%llx\n", ino); 345 return err; 346 } 347
